


Compounding Interest

by hey_malarkey



Series: Investments [2]
Category: Gravity Falls
Genre: Anal Fingering, Dubious Consent, Incest, M/M, Prostate Stimulation, Sea Grunkles, Sibling Incest, a little bit of after care, fluffier than you'd expect, interglutal sex
Language: English
Status: Completed
Published: 2019-03-27
Updated: 2019-03-27
Packaged: 2019-12-25 11:14:37
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,070
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18260147
Author URL: https://archiveofourown.org/users/hey_malarkey/pseuds/hey_malarkey
Summary: Picking up where the first part left off, how their relationship progresses in one night, and how Ford feels about these rapid developments.





	Compounding Interest

Stan pulls him back into a kiss, deeper this time, momentum carrying them back until Ford’s head bumps the wall. Stan pins him there, pushing one leg between Ford’s, already going so much faster than he expected but—

But he promised himself he’d keep Stan happy. So he kisses back and moans in all the right places. It’s not unenjoyable, and it’s the first touch that has been human in decades. But it’s still weird.

But it’s worth it, to keep Stan. If this is the price he has to pay for every misfortune he’s brought his brother, then he’ll pay it. He owes it to Stan. He owes it to the life he’d ruined for his brother.

They fumble through the ship, back to the bedroom.

Ford laughs internally and Stan laughs out loud when he remembers their foresight to just get one big bed, easier to fit in their space, they have a dividing pillow and everything. Stan pushes him down on the bed, and Ford’s internal laughter turns a bit hysterical as Stan is a little more…enthusiastic than he’d anticipated.

Stan doesn’t  _rip_ any of his articles, but he is efficiently stripped in a very short period of time.

And in between rolling his sweater off his body, Stan is feeling up every inch of Ford, searching him as if he had hundreds of dollars taped to him.

Stan’s lips meet Ford’s again and Ford isn’t sure if he should be de-clothing Stan as well when Stan does it himself, shucking off his pants and now his body is pinning him to the bed and it’s a lot more than he expected.  _Literally_ , as he feels Stan’s erection growing against him and his brother grinding down against him.

Stan produces lube from  _who knows where_  and pours it over a couple of fingers. He breaches Ford with one finger, poking in and out, and it is  _weird_. After a few moments he adds a second finger, and he moans as a small, burning rush goes through him. Stan pats his thigh with his free hand as his other mercilessly runs in and out. He crooks his fingers _just right_  and that pain explodes away into pleasure, hitting something inside of him he didn’t know he had.

“Stanley! Oh-,”

“Heh, there it is,” Stan grins wide and finds it again. It’s overwhelming, and Ford tries squeezing his legs together to keep it from overwhelming him. But Stan isn’t slowing and he hasn’t been touched like this in  _years_ and-

“Stan, Stan I’m gonna cum- _-ah! Stanley pl-”_  Stan grabs Ford’s dick and strokes him, hard and fast, and it’s all too much to handle right now. His body doesn’t care that it’s his brother doing this, his body doesn’t care that his mind is yelling  _WRONG, WRONG, WRONG_ even as his lips said yes, his body is coming hard and painting his chest white and his toes are curling and a yell is echoing around their small room as Stan strokes him until he’s dry.

Ford feels a little trembly and a little like crying and a lot like a towel wrung out to dry, sweaty and used. He looks up at Stan, who’s hovering over him, grin wide as he cards a cum-sticky hand through Ford’s hair, leaning over to kiss him.

“How was that for a first time? First time, right? We didn’t do this yesterday and I forgot? Heh, heh. Did I really rock the boat for ya, sailor?”

Stan looks satisfied with himself and waggling his eyebrows and he’s so  _Stanley_ in this moment, making a bad joke on top of a bad pun, and Ford can’t help but let out a puff of air that could be a laugh in response.

“Yeah, you definitely did, Stan,” Ford answers honestly. There’s a wave of shame that’s threatening to take him, right now, and he’s fighting to keep it at bay until he can be alone. But he’s naked and his brother is naked and he just got finger-fucked and it’s hard to keep a straight head after that.

Ford looks down and sees Stan’s dick is still hard. He hadn’t rubbed it out on him or gotten to fuck him. He hesitates for just a moment before knowing what he needs to do. At the very least, it’s only polite. At most, he owes this to Stan, too.

“Need some help, there?” Ford asks, a light question with a light smile and a nod down at Stan’s crotch where he could see the tip leaking pre-cum through his boxers.

Stan looks down between them and then back at Ford. “What exactly are ya offering?” he smirks and lowers his hips to rest against Ford’s. Stan lightly swivels his hips in small circles and the slight drag of the fabric against Ford’s sensitive dick post-orgasm makes him shudder as Stan grinds.

“W-well, that’s up to you,” Ford evades, not sure what he wants to give. What Stan wants from him. In the meantime he reaches up with one hand and cups the back of Stan’s neck, bringing him lower for a kiss. Stan complies, letting more of his weight settle on Ford as he deliberates. Ford can’t help the soft  _oomph_ he lets go as Stan lays on him.

Something about the weight seems like it should be oppressive, but it just feels so good, being surrounded, held down, unable or unwilling to move out from under him. Like his choices were taken away, like he can’t blame himself for what’s happening between them.

Ford deepens their kiss, fingers tensing on the back of Stan’s neck, and Stan’s soft swivels grow stronger.

“Mm,” Stan hums, leaning back from Ford’s lips, kissing across his jaw and scratching his scalp, hand still sticky and making a weird feeling settle through Ford. “I know what I want, if you want it. Flip over for me,” he requests, removing his hands and using them to shuck off his boxers, moving off Ford enough to let him do as requested.

There’s some rustling cloth noises and Ford peaks over his shoulder to see Stan tear off his shirt as well, both of them fully naked. When Stan next leans over him he can feel his incredibly hairy chest and gut pushing him down into the mattress. He turns his head sideways to breathe, resting on the pillow.

He also feels Stan’s dick wedge its way between Ford’s cheeks and for a moment he fears Stan will try and penetrate him so soon after his orgasm. He can only assume it would overwhelm his senses, the hazy feeling on him wearing off faster as that flash of fear hits him.

But then Stan kisses Ford’s neck, kisses his cheek, and doesn’t angle his hips for penetration. He starts rocking his hips, sliding his dick between Ford’s cheeks.

“Hey, clench up for me, will ya? You’ve got a fantastic ass, I’d love to use it,” Stan says, patting Ford’s ass with a few light swats. Not enough to really sting, but to get his point across. Ford turns his head, muffling a moan into the pillow. He does what Stan said, feeling the air pressed out of his lungs as Stan bears his full weight down on Ford.

“Sweet Moses, Sixer, how the hell do ya feel this good?” Stan groans behind him, hot breath tickling Ford’s neck as Stan rocks faster. He put no lube on, so it’s a dry rub between his ass, but it’s not terrible.

Fingers dig into Ford’s hips and Stan frots against him, pushing the air out of Ford as his brother bears down with every rock forward. Ford clenches, his entire body going tight and Stan speeds up further.

God, how did he end up here? Ford chokes back a couple of tears as Stan pants roughly in his ear, whispering dirty words and everything he wants to do together. He wants the exploration and the adventure, but before Stan’s even finished he’s questioning himself on why he lied about wanting  _this_ kind of love,  _this_ type of exploration.

“Mm, oh god, Ford,” Stan moans in his ear, turning and kissing him, seeking out his lips. Ford closes his eyes tightly, unable to stop his hips from wanting to rock back on his brother. His mind is fighting his body at this decision, but he just needs to get through a little bit more. He gasps out a breath as Stan presses him more into the mattress, fucking him down, hips rocketing and rubbing and managing to make it good for him, despite already making him cum. His dick is rubbing into the mattress and he mewls out a whimper at the sensations running through him.

“Sta-Stanley,” Ford pants, turning his head up as far as he can twist. Stan captures his lips again, kissing the life out of him as he rocks with abandon, balls slapping against Ford.

“ _Mmm, Ford-ohh!_ ” Stan moans as he finally comes, hips rocking through it, fingers pressing bruisingly into Ford’s hips and a little bit of drool dripping out of Stan’s mouth and onto Ford’s cheek.

When Stan finishes he collapses on Ford completely. He gathers Ford up in his arms, his forearms going under Ford’s head, holding his brother closer. Stan breathes deeply, sweaty forehead pressed to the back of Ford’s neck as he recovers.

Ford can feel his brother’s rapid heartbeat slowing down. A hand wiggles out and finds Ford’s, capturing it to interlace fingers. Stan brings their joined hands up to kiss the back of Ford’s hand. It’s a sweet gesture, reminding Ford of the affection his brother craves. The simple acts that mean so much to him. To both of them.

After a few minutes more Ford composes himself, turning to look at Stan. “We should clean up, Stan,” he suggests.

Stan nods, eyes heavily lidded, rolling to one side and pulling Ford with him. Ford feels the sticky slide of cum on his back as Stan shifts them over. Ford pats the arm around his chest and ducks under it, leaning on one elbow to look at his brother. Stan looks so content, so at peace. Ford can’t handle wiping that expression off his face. He refuses to be the reason Stan worries anymore.

He takes a breath and smiles, leaning down to peck Stan on the cheek. “I’ll be right back,” he promises, rolling off the bed and padding to the bathroom. He wets a washcloth with warm water, rinsing the semen off himself. He allows a few unsteady breaths as he talks himself through the logic of his decision.

He owes this to Stan. He  _wants_ to do this. And at the very least it will be…interesting. He finishes cleaning himself and walks back into their bedroom, leaning over Stan and carefully wiping him down, re-folding the washcloth to hang over their bed frame while it dried.

Ford finds his discarded underwear and his pajamas, pulling out a pair of Stan’s too, if he wants, and changing back into some clothes. Stan sits up, pulling on his boxers, leaving his chest bare.

Ford slips back into the bed, the dividing pillow thrown to the foot of the bed, into Stan’s waiting arms.

“I know we’ll be great together,” Stan whispers, gathering Ford’s back to his chest, kissing his neck, his shoulder, anywhere he can reach. Not to arouse, just for comfort. Just as when they were kids, Ford can’t help but feel a sense of safety and rightness for being with his brother, but it is distorted by this new relationship Stan has proposed.

But he’ll get used to it. Maybe he’ll even love it. But no matter what, he’d do it for Stan. His brother deserved the world, and the least Ford can do is give it to him. He folds a hand over where Stan’s hand is on his chest, the other reaching back to rub against the thigh of a leg flung over his own legs.

Ford forces himself to relax in those arms, to snuggle back further into Stanley. He goes through a breathing exercise that is supposed to help him sleep. It pushes his mind away from the wrongness of this scenario just enough that he can enjoy the warmth of the arms around him and hopefully convince his brother that he wanted this too.


End file.
